氧化纳米纤维素增强再生纤维素全纤维素复合薄膜的制备及性能

Preparation and properties of all-cellulose composite films with oxidized cellulose nanofibrils reinforcing regenerated cellulose

以2,2,6,6-四甲基哌啶-氮-氧化物(TEMPO)氧化松木粉纳米纤维素(TOCNs)为增强相、α-纤维素粉制备再生纤维素(RC)为基体,采用溶胶-凝胶法制备氧化纳米纤维素增强再生纤维素(TOCNs/RC)全纤维素复合薄膜。对不同TOCNs添加量下TOCNs/RC全纤维素复合薄膜的力学性能、光学性能、氧气阻隔性能和热稳定性能进行研究,并通过FTIR、SEM、TEM、XRD和流变仪对TOCNs和TOCNs/RC全纤维素复合薄膜的结构、形貌及纤维素溶液流变性能进行表征。结果表明,TOCNs添加量对TOCNs/RC全纤维素复合薄膜的力学性能有显著影响,当TOCNs添加量(与纤维素基体的质量比)为1.0%时,TOCNs/RC全纤维素复合薄膜的拉伸强度和断裂能分别可达134.3 MPa和21.51 MJ·m^-3,具有最佳的综合力学性能;TOCNs/RC全纤维素复合薄膜的透光率随TOCNs添加量的增加而下降,雾度随TOCNs添加量的增加而增大,但仍保持较高的透光率(>85%)和较低的雾度(<14%);TOCNs/RC全纤维素复合薄膜还具有优异的氧气阻隔性,TOCNs添加量为1.6%时,其透氧系数仅为1.47×10^-17cm^3·cm/cm^2·s·Pa。TOCNs/RC全纤维素复合薄膜有优于一般塑料薄膜的拉伸强度和氧气阻隔性,并有可媲美于塑料薄膜的透明度,可作软包装复合材料的强度层和阻隔层,在绿色高性能包装材料领域具有广阔的应用前景。

The oxidized cellulose nanofibrils reinforcing regenerated cellulose(TOCNs/RC)all-cellulose composite films were prepared with 2,2,6,6-tetramethylpiperidinooxy(TEMPO)oxidized cellulose nanofibrils of pine powder as the reinforcments and RC ofα-cellulose powder as the matrix by the sol-gel method.The properties of mechanical,optical,oxygen barrier,thermal stability of TOCNs/RC all-cellulose composite films with different mass ratios of TOCNs to RC were investigated.The structure,morphology of TOCNs/RC all-cellulose composite films and the rheology of cellulose solution were characterized by FTIR,SEM,TEM,XRD and rheometer.The results show that TOCNs have significant effects on the mechanical properties of TOCNs/RC all-cellulose composite films.The tensile strength and fracture energy of TOCNs/RC all-cellulose composite films reach at 134.3 MPa and 21.51 MJ·m^-3 respectively with TOCNs content of 1.0%(mass ratio to cellulose matrix),which has the best comprehensive mechanical properties.The transmittance decreases and haze increases as the augment of the mass ratios of TOCNs,but TOCNs/RC all-cellulose composite films still maintain high transmittance(>85%)and low haze(<14%).The TOCNs/RC all-cellulose composite films also have excellent oxygen barrier property and the oxygen transmission coefficient reaches a minimum of 1.47×10^-17cm^3·cm/cm^2·s·Pa at 1.6%TOCNs.The TOCNs/RC all-cellulose composite films have better tensile strength and oxygen barrier property than general plastic films and also have comparable transparency,which can be used as the strength or barrier layer for the flexible packaging composites and have profound application prospects in the field of green and high-performance packaging meterials.